The following matters are known as first background art. In taking a still image or a movie with a camera or displaying the still image or the movie on a monitor, various image processing technologies have been developed in order to improve sharpness and clarity. For example, a contour enhancement process to improve the sharpness and a color saturation enhancement process to improve the clarity are exemplified as the image processing in related art. In addition, the image processing to adjust a sense of depth includes a method using depth data, for example, disclosed in PTL 1. In PTL 1, sense-of-depth correction gain is controlled using the depth data and a degree of depth to freely adjust the degree of the sense of depth. The depth data is acquired using an active method and a passive method. The active method includes Time Of Flight (TOF) in which infrared light is radiated to calculate a distance from reflected light. The passive method includes stereo cameras that perform matching using stereo images to calculate parallax.
However, the method disclosed in PTL 1 has a first problem in that, since accuracy and resolution in long-distance view are reduced when the depth data is acquired using the active method or the passive method, the adjustment in the long-distance view in accordance with the depth is disabled not to possibly provide the sense of depth. In the active method, the accuracy and the resolution depend on the irradiation intensity of the infrared light and all distances are at infinity in the long-distance view in which the reflected light of the infrared light cannot be detected to reduce the accuracy and the resolution. In the passive method in which the parallax is calculated with two cameras that are arranged in parallel, the parallax is inversely proportional to the distance and the parallax in the long-distance view is equal to zero to reduce the accuracy and the resolution.
In addition, the following matters are known as second background art. In taking a still image or a movie with a camera or displaying the still image or the movie on a monitor, various image processing technologies have been developed in order to improve the sharpness and the clarity of the still image or the movie. For example, the contour enhancement process to improve the sharpness, the color saturation enhancement process to improve the clarity, and image processing in which the depth data is used to adjust the sense of depth are known.
The control of the sense-of-depth correction gain using the depth data and the degree of depth by an image processing apparatus to adjust the degree of the sense of depth is disclosed in PTL 1. The depth data is acquired using the active method and the passive method. The active method includes the Time Of Flight (TOF) in which the distance to an object is calculated from reflected light of infrared light with which the object is irradiated. The passive method includes a method of calculating the parallax by the matching using stereo images that are taken by stereo cameras.
However, PTL 1 has a second problem in that, when the depth data is acquired using the active method or the passive method, the accuracy and the resolution in the long-distance view are reduced. For example, in the active method, since the accuracy and the resolution depend on the irradiation intensity of the infrared light, all distances are at infinity in the long-distance view in which the reflected light of the infrared light cannot be detected. In other words, the resolution of the depth is lost in the long-distance view in which the reflected light of the infrared light cannot be detected to disable accurate representation of the depth.
In contrast, in the passive method, when the parallax is calculated as an example of the depth data with two cameras that are arranged in parallel, the parallax is inversely proportional to the distance and the parallax in the long-distance view is equal to zero. In other words, the resolution of the depth is lost in the long-distance view to disable accurate representation of the depth. As a result, the image processing apparatus in the related art is not capable of performing the image processing corresponding to the depth in such long-distance view to cause a user not to sufficiently feel the depth.
Furthermore, the following matters are known as third background art. In taking a still image or a movie with a camera or displaying the still image or the movie on a monitor, various image processing technologies have been developed in order to improve the sharpness and the clarity. For example, the contour enhancement process to improve the sharpness and the color saturation enhancement process to improve the clarity are exemplified as the image processing in the related art. The image processing to adjust the sense of depth includes a method using the depth data. For example, the control of the sense-of-depth correction gain using the depth data and the degree of depth to freely adjust the degree of the sense of depth is disclosed in PTL 1.
In the image processing to adjust the sense of depth in accordance with the depth data, it is necessary to appropriately set the depth data and image processing parameters. FIG. 33 is a graph illustrating the relationship between the depth data and contour correction gain in PTL 1. As illustrated in FIG. 33, keeping the sense-of-depth correction gain constant against the variation in the depth data in an area in which the depth data has a value lower than a first depth value Z30 and an area in which the depth data has a value higher than a second depth value Z31 is disclosed in PTL 1.
However, there are a case in which only the depth data having a value lower than the first depth value Z30 exists or a case in which only the depth data having a value higher than the second depth value Z31 exists depending on the image. The image processing apparatus in PTL 1 has a third problem in that, since the image processing apparatus in PTL 1 is not capable of setting appropriate image processing parameters in these cases, it is not possible to adjust the sense of depth for the image to cause the user not to feel the depth.